command 0.0.8

command

This is a simple command-line framework that I devised while writing a "very secret" project for an internship.

Status

This library is still in-dev.

PLEASE NOTE: By default, the library will *NOT* spawn a new thread and read from stdin. This functionality is *opt-in*, and you MUST compile the library with the `cli` version for this. This is done via:

// dub.sdl
subConfiguration "command" "cli"
// dub.json
"subConfigurations": {
    "command": "cli"
}
    

ADDITIONAL NOTE: Compiling the library with the `cli` will bring in `linenoise` as a dependency.

Design Goals:

• Lightweight
  • Minimal dependencies (only 2, but 1 is optional)
• Portable
• Easy to use

Examples

Untyped example:

class TestExample {
@CommandNamespace("test"):
    // name, description, min args, max args
    @Command("hello", "Hello, World!", 0, 0)
    string hello(string[] args) {
        return "Hello, World!";
    }

    @Command("user", "Say hello to someone!", 1, 1)
    string hello_user(string[] args) {
        return "Hello, " ~ args[0] ~ "!";
    }
}

mixin RegisterModule!TestExample;

Typed example:

class TestExample {
@CommandNamespace("test"):
    // example with no parameters
    @TypedCommand("hello", "Hello, World!", 0, 0)
    string hello() {
        return "Hello, World!";
    }

    // any POD parameter is allowed here (float, string, double, integer, etc)
    // as well, the return type may be any POD
    @TypedCommand("user", "Say hello to someone!", 1, 1)
    string hello_user(string user) {
        return "Hello, " ~ user ~ "!";
    }

    @TypedCommand("meaning_of_life", "What is the meaning of life?", 0, 0)
    int meaningOfLife() {
        return 42;
    }
}

then, in the CLI:

> test.hello()
Hello, World!
> test.user("Foo")
Hello, Foo!
> test.user(test.hello())
Hello, Hello, World!!

(also found in command:greeter)

TODO:

• Proper return types
  • Avoid using strings as a type everywhere
• Small standard library for ease of use
  • No user-defined functions however
    • By design, we're not trying to be a scripting engine
• Well-defined instantiation order
  • In the end, this won't matter (since you can't call until the engine has been fully initialized), but might be worth investigating